Pneumatic hammer.



E. G, DETRICK.

, PNBUMATIG HAMMER.

APiLIoATIoN FILED SEPT. 25, 1913. v f

Patented Aug. 25, 1914.,

2 SHEETS-SHEET 1` mm, ATTORNEY B. G. DETRIGK. a PNEUMATIG HAMMER.

APPLICATION FILED SEPT. 25, 1913.

Patented Aug. 25 1914, Y

2 SHEETS-SHEET 2` IIIII WITNESSES ATTORNEY .EMMETT Gr. DETRIGK, FVCKS'BURG, MISSISSIPPI.

'PNEUMATIC HAMMER.

. Specication of Letters Patent.

Patented Aug. 25, 1914.

Application led September 25, 1913. Serial No. 791,803.

To all whom t may concern l -Be it known that I, EMMirri` G. DETRICK, acitizen of the United States, residing at Vicksburg, in the county ofWarren and State, of Mississippi, have invented a new and usefulPneumatic Hammer, of which lthe following is a specification.

l, This invention has reference to improvements in pneumatic hammers,and is to be understood as useful for any purpose where av rapidsuccession of blows is desired.

' It is the object of the present invention to provide a pneumatichammer structure of extreme simplicity and at the same time one that isreliable in operation and not liable to become disabled because of thepresence I. of obstructing matter, since the device of the presentinvention is largely self cleaning and is free from allcomplicatedparts.

ln accordance with the present inventionthere is provided a freelyreciprocable plunger or hammer designed to deliver a succession of blowsto a suitable tool or tool holder and the body of the structure hascertain ducts and ports to which the hammer is relatedA as areciprocable valve, while the exhau'st is always freely openand henceoers n o impediment at anytime to the escape of air. The structure isfurnished with valves which, however, are' springless Iand respondsolely to air pressure, and these valves are so related to the hammerthat vthe air for reci' rocation of the hammer.

their operation is not afterward directed to the hammer, wherefore thefull and direct force of the air is always utilizable for the tudinalsection of a pneumatic hammer embodying the invention.l and showing .theplunger atthe termination of its act-ive stroke. Fig. 2 is a section onthe line 2-2 of Fig. 1.` Fig. '3 is a fragmentary section similar toFig. 2 and showing the hammer at the beginning of as active Stroke. Fig.i isa sec-tion on the line 4-4 of Fig. 1. Fig. 5 is a perspective viewof a valve block employed in the structure. Fig. 6 is an end view of thevalve block as seen from the opposite end to that shown in Fig, 5. Fig.7 is a section on the line 7-7 of Fig. 4c. Y

Referring to the drawings, there is Shown an elongated body member 1usually cylindrical in cross section and terminating at one end in alaterally expanded head 2. Extending axially through the body 1 is abore 3 which may be of equal diameter throughout, and is laterallyexpanded into a counterbore et within the head 2. That end of the bore 3remote from the head 2 contains a sleeve 5 having a longitudinal passagetherethrough of smaller diameter than the bore 3, and this sleeve isdesigned to receive a stem 6 on the corresponding end of a tool holder47 such as is customarily employed in pneumatic hammers, the term hammerbeing used as comprehensive enough to cover the use of the tool of thepresent invention for any purpose to which it islap'plicable.

Extending longitudinally through Vthe body member 1 to one side of thebore 3 is a duct or passage 8 of a length equal to that of the bore 3between the counterbore 4 and the inner end ofthe sleeve 5, but at onepoint this duct 8 is interrupted by a web or wall 9. The duct 8 hasports 10, 11, 12 and 13 opening therefrom into the bore 3 atrespectively different points. The ports 11 and 12 are on opposite sidesof the web or wall 9, while the port 10 is between the port 11 and theAhead 2, and the port 13 opens into the bore 3 closely adjacent to theinner end of the vsleeve 5. On the opposite side of the body 1 or at anyother appropriate point the body 1 has another longitudinal passage 14of less length than the passage 8, and this passage has ports 15 and 16opening into the bore 3. The port 15 is closer to the head 2 than theport 10 and the port 16 is located between theports 12 and 13 in thedirection of the length of the body 1, but closer to the'port 12 than tothe port 13.

At other points about the body member 1- are longitudinal ducts orpassages 17 and 18, respectively, exterior to the bore 3, the passage 17being as long as the passage 8 and provided at the end corresponding tothe inner end of the sleeve 5 with a port 19 0pening into the bore 3,the ports 13 and 19 being located at about the same distance from thehead 2. The passage 13 is shorter than the other passages and extendsfrom the head 2 but a relatively short distance and at its inner end isprovided with a port 20 opening into the bore 3 closer to the head 2than the port 10. For convenience the passages 8, 14, 17 and 18 aredisposed about the bore 3 in approximately ninety degree relation, butthis is not obligatory. However, for reasons which will hereinafterappear, the passages 17 and 18 are arranged approximately diametricallyopposite one to the other. The passage 18 is also provided at theendadjacent to the counterbore 4 with a port 21 opening into the bore 3.

Fitted to the bore 3 so as to reciprocate therein freely yet snugly, isan elongated hammer or plunger'22 having a reduced central ortion 23producing a groove 24 cir cumfleirentially about the middle part of theplunger.

Seated in the counterbore 4 is a block 25 shown as cylindrical in form,although not necessarily so, but such form .is the most convenient vtolthrough the block 25 is a passage 26 having laterally expanded ends 27each closed by aj'scre'w plug 28 and from each expanded portion 27 there.extends a'port 29, 30, respectively, in alinement with the respectivepassages v17 and 18, and constantly open thereto. Each enlargement 27where it joins the corresponding end of the passage 26 is formed into avalve seat 31 yadapted to recei've a valve 32, 33, respectively, eachhaving a stem 34 entering the passage 26, and these stems are 'ogsuchlength that when one valve i is seated'the other valve is held away fromits seat. rI rhe passage 26 at about a mid point communicates constantlywith a pas sage 35 extending radially through the block 25 and openingat the periphery thereof and n'ear the outer end this passage 35 has aport 36 in line and constantly communicating with the passage 14.

' Extending through the block 25 in parallelism with the axis thereo'fislanother pas# sage 37v in constant communication with the passage 8where it opensinto the counterbore 4, while still another passage 38 isformed through the block 25 parallel with the axis'of the block toaccommodate a'pin 39 having one end seated in asocket 40 ap*`propriately formed in the head 2, so that when the block 25'islodgedwithin the counterbore 4 the pin 39 maintains itin properposition. The pin 39 is to be taken as typfor holding the block 25 inconstant relation with the parts with which its passages communicate.

The head 2 is seated in a socket' member' 41 having a handle 42 formedonor secured 'thereto and the handle 42 need not di'er materi ally fromhandles as customarily provided for pneumaticA hammers. In theconstruct. Diametricallyv incassa drawings the exterior of the head 2and the portion of the socket member 41 receiving the head 2 are shownas correspondingly screw threaded, but even in this particular theshowing of the drawings need not be strictly followed. The head 2 has fom d therethrough a radial passage 43 com n1- cating with au opening orport 44 rough the socket member 41 and the 'Ssages 43 and 44 are in linewith the passage 35 and in constant communication t erewith. Since theparts may not alway/s lit accurately lthe inner wall of the head 2 isprovided with a circumferential groove/f' 45 and numerous passages 46are formed through the head in addition to the passage 43, while theinner 'control of a manipulating lever 51 on the handle 42, so arrangedthat when the handle is grasped the valve 50 may be opened thusadmitting air to the passage 8. The valve 50 and its manipulatingdevices may follow the usual practice and hence need no specialdescription. The socket member 41 is formed with a shallow recess 52where coming in contact with the block 25 so that air entering the toolmay be distributed certainly to the passage 3 Let it be assumed that inthe state of inaction the parts are in the position shown in F ig. 1with the plunger 22 against the stem 6 at the end of the bore 3 remotefrom the head 2. Under these circumstances-one of the valves 32 or 33 isseated, but it is immaterial which one this may be. The operator graspsthe handle 42 and by pressure on the lever 51 causes `the openingv ofthe lvalve 50 and air under pressure is admitted to the passage 8, itbeing assumed that an air hose is connected to the socket 49. In theposition of the parts assumed the port 1Q is closed or blanked by thecorresponding larger end of the plunger 22 and the port 20 is alsoclosed thereby, whilethe other larger end of" the plunger 22 closes theport 16. However,-

the ports 11`and 12 arein communication through the groove 22 then.bridging these ports, andthe port 13 is o ene to the bore 3 between thecorrespon" in l K y end.` of the plunger and the innerA end the y sleeve5,

' 125 lthe plunger b einghel'd awayfromthe' sleeve, by a sllght-projection ofthe stem`6 into the' bore 3. Air undervpressure'thereforefinds its way along,the 'passage 8 thrughthepor't into the groove 24andfrom thence by 130 way of the port 12 into the continuation of thepassage 8 on the other side of the web 9 and by way of the port 13 intothe bore 3 and exerts its pressure upon that end or head of the plunger22 at the time engaging the stem 6. The air under pressure also inds itsway from the bore 3 through the port 19 into the passage 17 and fromthence into the enlargement 27 containing the valve 33 and if at thetime this valve is open, the air under pressure immediately closes itand at the same time causes the opening of the valve 32. The compressedair at once impels the plunger 22 away from the stem 6 toward the block25 and this causes the progressive closing ofthe ports 12 and 11 and theultimate opening of the port 10 to the groove 24. The initial movementof the plunger 22 is unimpeded because air within the bore 3 between theplunger and the head 25 finds ready escape through the port 15 into theexit passage 14 which is always in free communication with theatmosphere through the port 36, passage and passages 43 and 44. Theplunger quickly closes the port '15, but still there is an exhaustpassage for air within the bore 3 between the plunger and the block 25by way of the ports 21 and 30, and the passage 26 where opened by thevalve 32, said passage 26 being at all times in free communication withthe atmosphere through the passage 35. The expansive force of the air isexerted upon the plunger to move it toward the block 25 until ulti- .airis under greater pressure than the air tending to hold the valve 33closed, the latter valve is forced open and the valve 32 is closed, thuscutting off the escape of air from the bore 3 between the plunger andthe block 35 before the plunger reaches the block 25, and, moreover, therapidly diminishingk space within the bore 3 receives air under fullpressure thro-ugh the port 21. Simultaneouslv with the establishment ofthe conditions just named the other end of the plunger has moved to aposition to uncover the part 16 to the end of the bore 3 first receivingair unoler pressure, while the passage 17 always communicating by theport 19 *with the end of the bore 3 remote from the block 25 is now incommunication with the atmosphere through the open valve 33. The rapidaccumulation of air pressure between the plunger andtheI block 25 notonly interposes a strongl air cushion preventing the plunger fromreaching the block 25, but full air pressure at once acts upon the block25 to drive it toward the stem 6 which it strikes with all the forceimparted to it by the air pressurebehind it, for air pressure is notagain established at the striking end of the plunger until the port 12is uncovered, which does not take place until approximately the timethat the blow is struck. Then,and then only, is there established an airpressure-sufficient to reverse the valves and returnV the plunger to thebeginning of its power stroke.

The air cushion established between theV plunger and the head 25 at thetermination of the retractive movement ofthe plunger Aprevents any shockor jar which might occur should the plunger strike metallic parts,'andalso does away with the necessity of a buffer spring, while at the endof the power stroke the full force of the plunger is utilized with# outthe retardation by the establishment of bufing pressure or the presenceof a buiing spring. a

Experience has shown that the plunger will reciprocate at high speed,say, about two thousand strokes per minute, while the -power of thestroke is in excess of that of commercial forms of pneumatic hammers oflike air consumption.

No springs whatever are used in the working parts of the hammer, the twovalves employed being responsive solely to air pressure, and this airpressure is not weakened by performing work before it reaches thevalves, nor does any ofthe compressed air do any work before reachingthe plunger. Full power is therefore available for all the workperformed and the parts respond vigorously and with full efliciency.

The passages and ports can be made of ex,- ceptionally large size, sothat any particles liable to choke small assages, and which sometimesfind access t creto, have nomaterial effect upon the device of thepresent invention and should small particles of grit or the like findtheir way into the passages and ports the plunger readily vforces themout on its return stroke. valves 32 and 33 leak to some extent, it onlymeans a slight waste of air without a material reduction in theeflciency of thedevice.

All the ports through which the main air passes are controlled by theplunger and the `Even should 'the only valves other than the plungeritself opening into the bore on each side of the interruption, two otherducts each having a plurality of ports leading into thebore, with one ofsaid two ducts opening constantly to vthe atmosphere and the other ofsaid two ducts constituting both a live air and an exhaust duct, meansresponsive to live air bore said duct having its continuity linter-ymediately interrupted and provided with ports opening into the bore oneach side of the'interruption, ,another duct shorter than therst-namedduct and .provided with a plurality of ports opening .into the bore andsaidduct also opening constantly to the atmosphere, another duct in thebody member having a plurality of ports opening into the bore, a fourthduct extending longitudinally of the body member and communicating withthe bore at the end thereof into which the first-named duct leads, and avalve structure located at the opposite end of the body member/and therecommunicating with the third and fourth named ducts, said valvestructure being responsive to live air pressure su plied through thesaid ducts controllable t ereby and opening and closing said -Jducts'tothe atmosphere.

3. A pneumatic hammer comprising an elongated body member with alongitudinal bore and a live air duct extending longitu-` dinallythrough the body member and at one end opening into the correspondingend of the bore, said duct having its continuityintermediatelyinterrupted and provided withy ports opening into the bore on each sideof the interruption, another duct shorter than the irst-named duct andprovided with a plurality of ports opening into the bore and said ductalso opening constantly to the atmosphere, another duct in the bodymember having a plurality of ports opening into the bore, a fourth ductextending longitudinally of the body member and communicating with thebore at the end thereof into which the first-'named duct leads, and avalve structure located at the opposite end of the body member and therecommunicating with the third and fourth named ducts, said valvestructure being responsive to live air pressure supplied through thesaid ducts controlled thereby and opening and closing said ducts to theatmosphere, the valve structure comprising separate valves andVincluding a duct constantly open to the atmosphereat an intermediatepoint and provided at op- `posite sides with' oppositely directed valveseats for the valves.

4. A pneumatic hammer havingf'an elongated body member provided with alongitudinal bore and with air ducts leading into the bore and spacedapart to direct `air under pressure into opposite ends of the bore, andone of said air ducts also leading t0 the atmosphere, the .body memberbeing provided With an exhaust duct distinct from the velongated bodymember having an elongated bore, and a reciprocatory plungerftherein,saidk body member having air ducts with ports communicating with thebore and controlled by the reciprocatory plunger, certain of the ductsbeing arranged to receive live air-under pressure and direct it againstopposite ends of the plunger with onev of the live air ducts leading tothe atmosphere and another of the ducts serving solely as an exhaustduct, the device being provided with means responsive to airunderpressure and arranged to be operated by live air other than thatoperating the plunger Ifor controlling the exhaust of utilized air.

6. A pneumatic hammer comprising an elongated body member with an axialbore and a reciprocatory power plunger within the bore, a closure for,one end of the bore having a transverse duct therein with valve seatsat the ends 'andintermediately communicating with the atmosphere,`valves mounted \in the duct in operative relation to the valve seats,ducts leading through the body member and having ports communicat ingwith the bore and the ports and plunger' being related to cause thelatter to operate as a controlling member for the ports, one of theducts constituting a live air duct for supplying air under pressure, andanother of the ducts constituting an exhaust duct at all timescommunicating with the atmosphere, and others of the ducts communicatingwith the valve in the closure to supply live air thereto for operatingthe valves.`

7. A device of the type described compris.u ing an elongated body memberhavingan axial bore, and a reciprocatory plunger mounted therein, saidbody member being provided with a duct for live air and having portscommunicating with the bore, another duct having ports communicatingwith the bore and also' communicating with the atmosphere, a blockforming a closure for one end of the bore, a reciprocatory valvestructure within the block movable in a direction Jperpendicular to thelongitudinal axis of the bore, and ducts in the body membercommunicating with the bore and with the valves, thereciprocatoryplunger being re lated to the ports opening into the bore and b eingconstructed to control the ports to regulate the admission of live airto the bore to drive the plunger, and the admission of live air to thevalves to control their action.

8. A device of the type described comprising an elongated body memberwith an axial bore and with a counterbored head at one end, said bodymember being also provided with longitudinally extended ducts havingports communicating with the bore at different distances from thecounterbore, a reciprocatory plunger lodged in the bore and constructedto operate as a reciprocatory valve for the ports, a block lodged in thecounterbore and having ports equal in number to the ducts in the bodymember and each communicating with a respective one of the ducts in thebody member, and a valve structure in the block responsive to airsupplied through certain of the ducts, said valve structure controllingthe exhaust of air from certain of the ducts and the plunger controllinthe exhaust of air fromI the opposite ends o the bore.

9. A device of the type described comprising an elongated body memberwith an axial bore and having longitudinally disposed ducts insurrounding relation to the bore, one duct being provided with a breakin its continuity at an intermediate point with ports, two on oppositesides of the break and leading to the bore, and one of the ports enterinthe bore at one end thereof, another duct aving spaced ports enteringthe bore, and said duct being also provided with free communication withthe atmosphere, another duct having a port communicating with the boreadjacent tothe end port of the firstnamed duct, and still another ductcommunicating with the bore at its opposite ends and of less length thanthe other duct, a block forming a closure for the corresponding end ofthe bore and provided with ports communicating with each of the saidducts in the body member, reciprocatory valves within the block and eachcontrolling a respective port other than those communicating with thefirst-named duct and the duct connected to the atmosphere, the blockalso having a passage communicating with the atmosphere and controlledby the valves, and a plunger mounted in the bore to reciprocate thereinand constructed to control the port opening into the bore.

10. A device of the type described provided with a reciprocatory powerplunger and having live air ducts controlled by the power plunger forsupply"Wr air under pressure to operate the plunger, said device beingprovided with other live air ducts and an air exhaust duct controlled bythe plun ger, and an exhaust valve structure communicating with thelast-named live air ducts for receiving live air therefrom and in turncommunicating with the atmosphere to exhaust the said last-named liveair ducts.

11. A device of the type described provided with a reciprocatory powerplunger and lhaving live air ducts controlled by the power plunger forsupplying air under pressure to operate the plunger, said device beingprovided with other live air ducts 'controlled by the plunger, and anexhaust valve structure communicating with the lastnamed ducts forreceiving live air therefrom and in turn communicating with theatmosphere to exhaust the last-named live air ducts, an exhaust ductdistant from the ducts controlled by the valve structure and whollycontrolled by the plunger.

In testimony, that l claim the foregoing as my own, I have heretoaffixed my signature in the presence of two witnesses.

HERBERT A/SPDEN, J. D. MoCAnRoN.

Copies et this patent may he obtained. for .ve cents each, by addressingthe Commissioner n! Patents. Washingtom.

said device being also provided with`

